• 9-12: 3C/H5. Human inventiveness has brought new risks as well as improvements to human existence.

• 6-8: 4D/M1a. All matter is made up of atoms, which are far too small to see directly through a microscope.
• 9-12: 4D/H1. Atoms are made of a positively charged nucleus surrounded by negatively charged electrons. The nucleus is a tiny fraction of the volume of an atom but makes up almost all of its mass. The nucleus is composed of protons and neutrons which have roughly the same mass but differ in that protons are positively charged while neutrons have no electric charge.
• 9-12: 4D/H2. The number of protons in the nucleus determines what an atom's electron configuration can be and so defines the element. An atom's electron configuration, particularly the outermost electrons, determines how the atom can interact with other atoms. Atoms form bonds to other atoms by transferring or sharing electrons.
• 9-12: 4D/H3. Although neutrons have little effect on how an atom interacts with other atoms, the number of neutrons does affect the mass and stability of the nucleus. Isotopes of the same element have the same number of protons (and therefore of electrons) but differ in the number of neutrons.
• 9-12: 4D/H4. The nucleus of radioactive isotopes is unstable and spontaneously decays, emitting particles and/or wavelike radiation. It cannot be predicted exactly when, if ever, an unstable nucleus will decay, but a large group of identical nuclei decay at a predictable rate. This predictability of decay rate allows radioactivity to be used for estimating the age of materials that contain radioactive substances.

• 6-8: 11B/M1. Models are often used to think about processes that happen too slowly, too quickly, or on too small a scale to observe directly. They are also used for processes that are too vast, too complex, or too dangerous to study.
• 6-8: 11B/M4. Simulations are often useful in modeling events and processes.

• 6-8: 11D/M3. Natural phenomena often involve sizes, durations, and speeds that are extremely small or extremely large. These phenomena may be difficult to appreciate because they involve magnitudes far outside human experience.

• F-LE.1.c Recognize situations in which a quantity grows or decays by a constant percent rate per unit interval relative to another.
• F-LE.3 Observe using graphs and tables that a quantity increasing exponentially eventually exceeds a quantity increasing linearly, quadratically, or (more generally) as a polynomial function.

This lesson was created specifically to accompany the PhET simulation Nuclear Fission, giving guided direction to ensure students stay focused on learning goals. By using this printed guide, students will be prompted to think about what happens in a nuclear reaction, what makes a nucleus "fissionable" and how nuclear power containment vessels prevent a runaway chain reaction. We recommend introducing this simulation after first exploring a related PhET simulation, "Isotopes and Atomic Mass". Beginning learners need a foundation to understand factors that affect stability of an atomic nucleus.

• Physical Sciences K-8 Matter and Interactions Unit
• Physics First Matter and Interactions Unit
• Conceptual Physics Matter and Interactions Unit
• Algebra-Based Physics Matter and Interactions Unit
• AP/Calculus-Based Physics Matter and Interactions Unit

This lesson was created specifically to accompany the PhET simulation Nuclear Fission, giving guided direction to ensure students stay focused on learning goals. By using this printed guide, students will be prompted to think about what happens in a nuclear reaction, what makes a nucleus "fissionable" and how nuclear power containment vessels prevent a runaway chain reaction. We recommend introducing this simulation after first exploring a related PhET simulation, "Isotopes and Atomic Mass". Beginning learners need a foundation to understand factors that affect stability of an atomic nucleus.

• Physical Sciences K-8 Molecular Structures and Bonding Unit
• Physics First Molecular Structures and Bonding Unit
• Conceptual Physics Molecular Structures and Bonding Unit
• Algebra-Based Physics Molecular Structures and Bonding Unit
• AP/Calculus-Based Physics Molecular Structures and Bonding Unit

This lesson was created specifically to accompany the PhET simulation Nuclear Fission, giving guided direction to ensure students stay focused on learning goals. By using this printed guide, students will be prompted to think about what happens in a nuclear reaction, what makes a nucleus "fissionable" and how nuclear power containment vessels prevent a runaway chain reaction. We recommend introducing this simulation after first exploring a related PhET simulation, "Isotopes and Atomic Mass". Beginning learners need a foundation to understand factors that affect stability of an atomic nucleus.

• Physical Sciences K-8 Nuclear Processes Unit
• Physics First Nuclear Processes Unit
• Conceptual Physics Nuclear Processes Unit
• Algebra-Based Physics Nuclear Processes Unit
• AP/Calculus-Based Physics Nuclear Processes Unit